The present invention relates to optical non-linear material made of glass, and in particular to optical non-linear material containing micro crystal particles and a method for manufacturing the same.
Conventionally, information transmission using light, such as with the use of optical fibers, has found increasingly wider use for large-volume information transmission. Such information transmission systems require various optical functional elements. To manufacture such optical functional elements, materials having second-order optical non-linearity are important. As materials having second-order optical non-linearity, crystalline materials such as LiNbO3 are widely utilized. Meanwhile, it is desirable to use glass material in terms of a stable connection with an optical fiber, low loss of the transmitted light, low cost, and a wide rage of transmitting wavelength.
For example, Japanese Patent Laid-open Application No. Hei 10-111526 proposes that UV-excited poling is applied to Ge-doped SiO2-based glass to impart thereto a second-order optical non-linearity in which a d-constant, or an optical non-linearity constant, is 2.5 pm/V or larger.
As such, it has conventionally been proposed that UV-excited poling is applied to glass materials to impart remarkably large second-order optical non-linearity thereto. However, there has still been a desire to manufacture glass materials having larger second-order optical non-linearity more easily.
The present invention has been conceived in view of the above, and aims to provide a material having improved optical non-linearity and a manufacturing method therefor.
Non-linear material according to the present invention is characterized by the fact that micro-crystal particles, obtained by partially crystallizing a glass phase, are dispersed in the glass phase. Presence of micro-crystal particles enables development of large second-order optical non-linearity.
Preferably, the micro-crystal particles each have a diameter of 10 to 20 xcexcm.
Preferably, glass materials are subjected to UV-excited poling, in which UV strength is 10 mJ/cm2 or more and an electric field strength is 3xc3x97104 V/cm or more, so that a non-linear optical constant, or a d-constant, becomes 1 pm/v or more.
A method for manufacturing an optical non-linear material according to the present invention is characterized by the fact that glass material is subjected to partial crystallization. Generation of micro-crystal particles as above enables development of large second-order optical non-linearity in the glass material.
Preferably, glass materials are subjected to UV-excited poling, in which UV strength is 10 mJ/cm2 or more and an electric field strength is 3xc3x97104V/cm or more, so that a non-linearity optical constant, a d-constant, becomes 1 pm/V or more.
A method for manufacturing non-linear material according to the present invention is characterized by the fact that glass material is subjected to partial crystallization to disperse micro-crystal particles, or partially crystallized glass phase, and then to UV optical poling. That is, when glass material is subjected to partial crystallization in advance, second-order optical non-linearity can be developed in the glass material through UV-excited poling using a relatively low electric field.
Preferably, the partial crystallization is UV-excited poling in which UV strength is 10 mJ/cm2 or more and an electric field strength is 3xc3x97104V/cm or more, and UV-excited poling at a subsequent step is applied using a lower voltage than that which is used in the UV-excited poling for partial crystallization.